A turbofan engine conventionally includes rotor blades adapted to introduce air into an engine body and guide vanes, which are stator vanes adapted to straighten flow of air introduced by the rotor blades.
To meet a demand for an increased bypass ratio intended to improve fuel economy of recent turbofan engines, fan diameter tends to become larger, and consequently it is urgent to reduce weight of the turbofan engines.
For example, there are attempts to reduce the weight of the guide vanes themselves, which are stator vanes adapted to straighten flow of air, by using composite vanes made of a composite material of a thermosetting resin such as an epoxy resin and reinforcement fibers such as carbon fibers or light-metal vanes made of a light metal such as aluminum.
The guide vanes made of a composite material or a relatively soft metal such as aluminum are inferior in erosion resistance and shock resistance. Thus, to avoid wear, a metal sheath of hard material is bonded with adhesive to leading edge portions (leading edges and their vicinities) especially subject to wear due to head-on collisions with particles such as sand or pebbles (see, for example, Patent Document 1).
Of the guide vanes made of such a composite material or light metal, vane surfaces (vane surfaces excluding a metal sheath bonded to the leading edge portions) of vane bodies hit obliquely by particles such as sand or pebbles at shallow angles are coated, for example, with a soft polyurethane paint which has excellent erosion resistance against collisions of particles at shallow angles and is lighter than metal.